There are many compounds present in tobacco that contribute to its characteristics, such as its flavour.
To retain the quality and flavour of tobacco in a tobacco extract, it is desirable to retain some or all of those compounds that contribute to the tobacco flavour, such as nicotine and other aromatic compounds. However, many aromatic compounds are volatile, and they can therefore be lost during the process of producing and/or treating a tobacco extract, resulting in a tobacco extract with reduced or low levels of aromatic compounds.
During the preparation of tobacco extract, it can be necessary to include one or more concentration steps to achieve the desired concentration of compounds in the tobacco extract. Such concentration steps can lead to the loss of compounds, such as aromatic compounds, from the tobacco extract. Such concentration steps may alternatively or in addition lead to changes in the composition of the tobacco extract, leading to a change in the sensory aspects of the extract, such as the taste of the extract, which may transfer to the final product.
It can be necessary to treat the tobacco extract prior to use to remove microbes. Such treatments include pasteurisation by heating, the addition of anti-microbial agents, high pressure pasteurisation (pascalisation) and gamma irradiation, which can negatively affect the sensory quality and/or the composition of the tobacco extract.
The present invention seeks to provide a process for the preparation of a tobacco extract which overcomes one or more of these difficulties.